Messages in this thread Patch in this message | | | Date | Wed, 1 Jul 2009 14:48:05 -0700 | From | Sukadev Bhattiprolu <> | Subject | Re: [RFC][PATCH] Disable CLONE_PARENT for init |
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| This won't fix the problem. The child won't autoreap itself if ->exit_signal | != SIGCHLD. | | > If you want to make this change because of container-init issues, I think | > you should just say so independent of this global-init case. | | Yes, agreed, the comment looks confusing. | | Oleg
Here is an updated patch with comments fixed.
Roland pls ack again if this is better.
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Disable CLONE_PARENT for init.
When global or container-init processes use CLONE_PARENT, they create a multi-rooted process tree. Besides if the siblings of init exit, the SIGCHLD is not sent to init process resulting in the zombies sticking around indefinitely.
Changelog[v3]: - [Roland, Oleg] Simplify comment describing the change Changelog[v2]: - Simplify patch description based on comments from Eric Biederman and Oleg Nesterov. - [Oleg Nesterov] Use SIGNAL_UNKILLABLE instead of is_global_init()
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> --- kernel/fork.c | 8 ++++++++ 1 file changed, 8 insertions(+)
Index: linux-mmotm/kernel/fork.c =================================================================== --- linux-mmotm.orig/kernel/fork.c 2009-06-30 23:01:06.000000000 -0700 +++ linux-mmotm/kernel/fork.c 2009-07-01 14:43:10.000000000 -0700 @@ -974,6 +974,14 @@ static struct task_struct *copy_process( if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) return ERR_PTR(-EINVAL); + /* + * To avoid multi-rooted process-trees prevent global and container + * inits from creating siblings. + */ + if ((clone_flags & CLONE_PARENT) && + current->signal->flags & SIGNAL_UNKILLABLE) + return ERR_PTR(-EINVAL); + retval = security_task_create(clone_flags); if (retval) goto fork_out;
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